[Gabster]

I was having thermostat problems so yesterday I fitted a new one.
Disconnected battery before I started messing around.
To get to stat I unplugged and removed MAF sensor and intake pipe.
Fitted new Thermostat, no problem, plugged in the temperature sensor, put intake and MAF back on, reconnected the battery.
As soon as I restarted the engine the cooling fan started up and wouldn't go off. It was not doing this before.
Any ideas? Is there some kind of a ECM reset I need to do or have I disturbed a wire somewhere?
It was all going so well ....

 

[David C]

Points to a problem with the temperature sensor or its wiring.

If the ECU can't see the temperature sensor, it turns the fan on full time.

 

[Gabster]

Sorted! Took the relays out from in front of battery - cleaned - replaced. No fan but also no engine start! (No fuel). Wiggled the wires a few times and eventually got it to run (fan off). It obviously needs an auto electrician - dodgy connection somewhere

 

[David C]

The small relay bases are coloured.
Brown = Injection
Red = Fuel Pump
White = AC
Black = Low Speed Fan

High Speed Fan is one of the larger relays.